Quantum tunneling effects in ultra-scaled MOSFETs: A theoretical perspective on device miniaturization limits

Abstract

As semiconductor device technology relentlessly advances, Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) are being scaled to dimensions where quantum mechanical phenomena can no longer be neglected. In sub-10 nm and especially sub-5 nm technology nodes, quantum tunneling effects significantly impact the performance, power dissipation, and reliability of transistors. The primary quantum tunneling mechanisms gate oxide tunneling and source-to-drain tunneling result in leakage currents that challenge traditional design paradigms. This paper presents a rigorous theoretical analysis of tunneling mechanisms in ultra-scaled MOSFETs, emphasizing the role of the Schrödinger equation and the Wentzel-Kramers-Brillouin (WKB) approximation in modeling quantum transport. By exploring the dependency of leakage currents on geometric scaling, material parameters, and electrostatic control, we provide insight into the fundamental limits of device miniaturization. Simulated plots based on parameterized models illustrate the exponential growth of tunneling currents with decreasing oxide thickness and channel length. These trends underscore a looming bottleneck in further CMOS scaling, necessitating alternative materials and device structures. The study concludes that while tunneling cannot be entirely suppressed, it can be mitigated through intelligent design and materials engineering. This work provides a foundational framework for understanding the physics-based constraints shaping future transistor technologies.